The copending patent application provided a novel selective precipitation method for forming polymer particles and polymer-encapsulated particles useful as standards, as calibrators and, when the encapsulated substances are pigments, as liquid toners for electrophotographic application.
The referenced earlier method utilizes copolyamide polymers which result from the polymerization of polyamide monomers, such as Nylon-6, Nylon-6-6 and Nylon-12. These polymers have been particularly well suited to the encapsulation of pigments for employment as liquid toners used in electrophotographic toning applications. In addition, the use of polymeric seeds as encapsulants for forming core/shell composites was suggested generally.
However, further discoveries have been made whereby the formation of so-called core/shell polymer composites can be facilitated by employing other than the polyamide polymers. The resulting core/shell polymer composites are more suitable than those composites for use as standards and calibrators than those resulting from the specific composites disclosed in the prior application.
Further, the ability of employing the general methodology disclosed in the earlier patent application for encapsulating such substances as liposomes was not obvious from the disclosures in the pending application and is not believed obvious therefrom, as only inorganic pigments were described therein as encapsulate. The polymer-encapsulated liposome particles have utility as carriers for the lipid substances, such as cholesterol, lecithin and the like, for example.